CVE-2026-114618
Description
Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to 1.9.0, the default RFC 7523 JWTBearerGrant.get_audiences() returns an empty list, causing JWTBearerGrant.verify_claims() to require only that an aud claim exists without matching the current authorization server. An attacker holding a legitimate assertion for another service can present it to a server that shares the signing key and uses the default grant, obtaining an access token across a trust boundary. Implementations that override get_audiences() with the server's valid audience identifiers are not affected. This issue is fixed in version 1.9.0.
How to fix
- authlib1.9.0 or later
- authlib authlib1.9.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| authlibPyPI | v < 1.9.0 | 1.9.0 |
| authlib authlib | v < 1.9.0 | 1.9.0 |
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